Mammoth HP-5 User Manual
HP 5 Microprocessor Control for Mammoth
Water Source Heat Pumps
Operation and Maintenance Manual
Model: 71028004
Applies to: Single Circuit
Water-to-Water
Twin Circuit Units Without DDC Controls
MAMM‐WHSP‐IOM‐1HP5A(October2011) P/N71144918
HP 5 Microprocessor Control
Important!
These instructions are for use by qualified
personnel specially trained and experienced in
the installation of this type of equipment and
related system components. Some states
require installation and service personnel to be
licensed. Unqualified individuals should not
attempt to interpret these instructions or install
this equipment. Read these instructions carefully
before opening (unpacking), installing and
operating this heat pump unit.
Definition
The HP 5 Microprocessor unit is designed to
operate with Mammoth’s existing series of wall
thermostats:
Manual Changeover
Auto Changeover with Night Setback,
Night Setup and Override
This unit can be used with other heat pump
thermostats, but some features may not be
available.
Features
Low and high voltage protection.
Check microprocessor at startup – self-
diagnostic
Random start time delay from 5 to 35
seconds
Compressor anti-short cycle protection
for 300 seconds (5 minutes)
Compressor, fan and reversing valve
control
Condensate overflow protection
Compressor lockout with selectable
intelligent/manual reset
LED status on the board
Lockout alarm signal to an LED in the
wall thermostat in the event of a safety
circuit fault
Fan interlock to automatically energize
the fan whenever the compressor is on
Board operable on 50 and 60 cycle
power
Emergency shutdown from a field-
supplied signal
Unoccupied (night setback and night
setup) mode from a field-supplied
signal.
Dry contact alarm signal for connection
of a fault signal to a DDC controller.
Auxiliary dry contact for tie-in of a
motorized valve when the compressor is
on (or optional compressor status)
Night heating or cooling operation from
the wall thermostat (71117203,
71117204 or 71117205 thermostat
required)
Override of the unoccupied mode from
the thermostat for 2 hours (71117204 or
7111205 thermostat required)
Low and high pressure compressor
protection
Low pressure bypass with 0, 1, 2 and 3
minute selections.
Operation
INITIAL POWER-UP: When power is applied to
the controller from unit's 24-volt transformer, a
"green” LED will be illuminated and a 120
second time delay will occur before the fan,
reversing valve and compressor are able to
operate. The controller will perform a selfdiagnostic and voltage check.
LOSS OF POWER: On a loss of 24-volt power
to the board, all the outputs are de-activated. On
return of power, a 120 second time delay will
occur before the fan, reversing valve and
compressor are able to operate. After 120
seconds, the fan, reversing valve and
compressor are able to operate after a short
time delay.
RANDOM START: A 5 to 35 second time delay
of fan, reversing valve and compressor
operation will occur each time the unit comes off
shutdown mode, unoccupied mode and low/high
voltage mode. The random start time varies
each time it is activated; for example, the time
delay may be 5 seconds, then 12, then 30, then
17, then 32, then 6, etc.
The following descriptions assume Initial
Power-up and Random Start functions have
occurred.
MAMM‐WHSP‐IOM‐1HP5A(October2011) 2
FAN OPERATION: On a call for fan operation
from the wall thermostat “fan on" switch or from
a call for compressor operation, fan operation is
delayed for 2 seconds.
REVERSING VALVE: On a call for cooling from
the wall thermostat, the reversing valve is
energized after 4 seconds. Once the cooling
demand is satisfied, the reversing valve is held
on for 4 seconds before it is de-energized.
COMPRESSOR OPERATION: On a call for
cooling or heating from the wall thermostat,
the compressor is energized from the
compressor output terminal after 6 seconds.
Once the call for cooling or heating is satisfied,
the compressor shuts off immediately. At that
time, a 300 second (5 minute) timer begins to
prevent the compressor from re-starting even
though the wall thermostat may again call for
cooling or heating. During this 300 second
interval, the compressor will not be allowed to
restart. After the 300 second time delay elapses,
the compressor is allowed to start if the wall
thermostat calls for cooling or heating.
FAN INTERLOCK OPERATION: When
compressor operation is required, the fan is
automatically enabled 4 seconds before the
compressor, even if the wall thermostat is not
calling for fan operation. This makes sure the
fan will be on whenever the compressor is on.
SAFETY CIRCUIT OPERATION: The unit has
up to 4 safety circuits to prevent the compressor
from operating during abnormal conditions.
High Pressure Switch: If the refrigerant
pressure exceeds the high pressure setpoint, the high pressure switch opens
immediately and the unit goes into the
lockout mode
Low Pressure Switch: If the refrigerant
pressure falls below the low pressure setpoint, the low pressure switch closes
immediately and the unit goes into the
lockout mode after the amount of low
pressure bypass has been satisfied.
Optional Freezestat Switch: If the leaving
fluid temperature falls to 32°F, the freezestat
switch opens. After 10 seconds, the unit
goes into lockout mode.
Condensate Overflow Protection: If the
drain pan sensor comes in contact with
moisture for more than 30 seconds, the unit
goes into lockout mode.
LED STATUS:
ON Normal operating mode
1 Flash High pressure fault
2 Flashes Emergency shutdown mode
3 Flashes Freezestat switch
4 Flashes Condensate overflow fault
5 Flashes Low voltage fault
6 Flashes High voltage fault
7 Flashes Low pressure fault
LOCKOUT MODE: Lockout mode will occur if
any of the safety circuits are activated. In this
condition the compressor is de-energized, but
the fan operates if the wall thermostat is calling
for cooling or heating. The two lockout alarm
circuits are also enabled.
LOW AND HIGH VOLTAGE PROTECTION: If
voltage conditions are good, the unit performs a
self-diagnostic check for faults. If no faults are
identified, the “green” LED comes on with no
flashes. If the supply voltage falls below the
minimum or above the maximum, the reversing
valve, fan and compressor are de-energized.
LED lights will indicate the fault. Once the
voltage falls within an acceptable range, the unit
will restart without requiring a reset. All time
delays required for start-up of the fan,
compressor and reversing valve will take place
before the unit is re-started. The low voltage cutout is 21.6 VAC and the cut-in is 24.0 VAC. The
high voltage cut-out is 34.0 VAC and the cut-in
is 29.7 VAC. These high and low voltages are
monitored at terminals “R” and “COM”.
LOCKOUT ALARM (CIRCUIT) SIGNAL: This is
the first lockout alarm circuit. In the lockout
mode, the circuit provides a 24-volt power (+)
signal at the “LO ALM” terminal of the terminal
block which is wired to the LED on the wall
thermostat to indicate a lockout condition.
DRY CONTACTS LOCKOUT ALARM
(CIRCUIT) SIGNAL: This is the second lockout
alarm circuit. In the lockout mode, this circuit
provides a signal at the terminal block. The
signal is a set of normally open contacts at
terminals "IN ALM" and "OUT ALM" of the unit
terminal strip. The contacts close in the lockout
mode, allowing connection of a remote alarm.
RESET OF A LOCKOUT: The controller can be
selected to manual or intelligent reset of a
lockout mode through an on-board dip switch
labeled as “RST”. When a manual reset is
selected, the unit stays in lockout until it is
MAMM‐WHSP‐IOM‐1HP5A(October2011) 3
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